Many urbanized areas in the United States are running out of potable water and improvements in water quality are becoming increasingly difficult and expensive to attain. Most of these environmental problems are related to the proliferation of impervious (paved or constructed) surfaces. Imperviousness has a double-edged effect that disconnects rainfall from groundwater thus interrupting the hydrologic cycle and reducing groundwater recharge and baseflows in rivers and streams while augmenting flooding problems, instream erosion, stormwater runoff, and increasing frequency of Combined Sewer Overflow (CSO) discharges. For a general treatise on the hydrologic cycle, the interaction of ground water and surface water, and water management, see Winter et al., Ground Water and Surface Water: A Single Resource, U.S. Geological Survey Circular 1139, U.S. Government Printing Office, Denver, Colo., 1998, 79 pp., the teachings of which are incorporated herein by reference.
Imperviousness is generally associated with growth and growth is associated with greater water demand. The consequence is that there is less water stored while more water is demanded. Additionally, each summer demand for potable water doubles in many communities as residents seek to irrigate their lawns, while in urbanized areas a preferred method of treating wastewater is through large regional systems that move water out of basin or sub-basins. The result is that demand for potable water frequently exceeds supply and causes many communities to enforce water bans during the summer months.
There is therefore a need for a system to mitigate the effects of urbanization on water resources, including reduced aquifer recharge, greater human demand, the proliferation of regional wastewater treatment facilities, and lack of conservation.